Four days that shook the world

By Kate Ravilious

THE Earth exploded under their feet. Noxious gases spouted into the atmosphere and quickly circulated around the globe. The ground shook with the force of a hundred massive earthquakes, and 20 gigatonnes of the Earth’s crust and mantle were blasted into the sky before raining back down onto the surface. It was a terrible day for the dinosaurs. They never recovered.

Is this, at last, a true description of what happened 66 million years ago? The argument over what killed the dinosaurs has raged for 25 years, and has polarised into two opposing camps&colon; a meteorite impact, or a prolonged bout of mega-volcanism called a continental flood basalt.

But now a team from Geomar, an earth sciences institute at Kiel University in Germany, has come up with a completely new type of geological catastrophe to explain the death of the dinosaurs, as well as three previous mass extinctions. If they are right the culprit was neither a meteorite nor a flood basalt, but a colossal underground explosion called a Verneshot.

As yet the idea is in its infancy (Earth and Planetary Science Letters, vol 217, p 263). But the Verneshot hypothesis has one big advantage over its rivals. It explains a mystery that haunts the debate over mass extinctions&colon; why the extinctions always seem to coincide with both continental flood basalts and meteorite impacts when the odds of these happening simultaneously are vanishingly slim.

In the past 400 million years there have been four major mass extinctions. Between 380 and 364 million years ago the Frasnian-Fammenian extinction pulses wiped out 60 per cent of marine life. That was followed ...

To continue reading this premium article, subscribe for unlimited access.